The preparation of forest estate models for strategic level planning requires a statement of the forest’s current biological condition,as well as forecasts of how stands are expected to develop over time (Erdle and Sullivan 1998). The current forest state is provided by a forest inventory that captures useful attributes of stand condition,
typically age and species composition. The complexity of long-term harvest scheduling necessitates the aggregation of these stands into strata, based on a classifi cation that groups stands of shared species and age attributes. The development patterns of these strata are represented by a set of yield curves, usually forecasting the yield of merchantable volume, but which may also indicate product quality and habitat suitability.

Challenges arise when inventories become dated, and intervening events change the forest condition. Fire, harvesting, and renewal activities are typical events that must be refl ected in updates to a forest inventory when preparing for strategic planning.Insect outbreaks are more complex to accommodate, especially when within-stand mortality is incomplete, and changes in growth are invisible to aerial reconnaissance. Yet, the change in stand structure caused by differential species mortality and the loss in growth of surviving trees, when aggregated across the forest, may have important consequences for harvest scheduling and sustainable harvest rates.

At the operational level, disturbance events like fire require the identifi cation of stands for salvage harvesting and renewal. However, insect outbreaks, which can be less discrete in time and space than fire, often provide less identifiable targets for salvage operations.

A recent outbreak of spruce budworm (Choristoneura fumiferana Clem.) on Kimberly-Clark’s Kenogami Forest in the boreal forest of northwestern Ontario has resulted in considerable merchantable volume loss of balsam fir (Abies balsamea(L.) Mill.) and white spruce (Picea glauca (Moench) Voss). However, the last Forest Resource Inventory (FRI) on the Kenogami Forest was completed in 1988, before the outbreak. Another inventory will not be completed until 2005 or later, too late for inclusion in the next (2005-2010) Forest Management Plan. A cost-effective means of determining the standing volume of the current forest, as well as determining the impact on future harvest volume forecasts, is required.